Improvement in wood-screws



L S;RUSSELL.

Wood-Screws. No.v 146,023. Y Patented oms-o, ma.

UNITED STATES PATENT OEEIoE` ISAAo S. RUSSELL, 0E NEW MARKET, MARYLAND, ASSIeNoR oE ONE-HALE EIS RIGHT To HENRY R. RUSSELL7 0E wooDRURY, NEW JERSEY.

IMPROVEMENT IN WOOD-SCREWS.

Specification forming part of Letters Patent No. 146,023, dated December 30, 1873; application filed August 7, 1873.

To all whom it may concern Be it known that I, ISAAC S. RUSSELL, of

` New Market, Frederick countv, Maryland, have passes; and to effect thiS, I give to the thread a varying pitch, decreasing gradually from the point throughout the Whole of its length,

A as is clearly represented by the accompanying drawing.

It is obvious that if a portion only of the threads have the gradually-decreasing pitch described, the eiiect of those threads would be the same-di'ering only in degree-as if all were of varying pitch; but

What I clailn as my invention, and to Secure by Letters Patent, is

A wood-screw, with a thread of varying pitch, gradually decreasing from` the point throughout the whole of its lengt-h, as Shown and described.

desire ISAAC S. RUSSELL.

Witnesses JOEL HALL, KATE HALL. 

